Some questions:

What is a thriving entertainment industry? Why do you assume it no longer exists? Currently they are still dominant in the sinosphere for films, TV and music.

I know that Cantonese became an official language in HK in 1974 which led to an increase in the popularity of Cantonese media. This may be what you refer to as thriving.

Are piggy backing questions allowed here?

I took a film class in college and my professor talked a lot about the mix of eastern and western customs in Hong Kong films. Has there been any sort of noticeable shift in the film industry since England "gave back" Hong Kong?